With Halloween arriving on Thursday, you’re probably going to be watching a horror movie or two over the next few days (and Vulture has some good recommendations from Netflix Instant). For pure pant-sh*tting terror, I’d go with Gravity in 3D, which is not a horror movie, but it’s more terrifying than most, or you can choose from among the best horror movies of the last decade. To help get you in the spirit, I scoured the Internet in all the usual places (tumblr, deviantart, pinterest, etc.) and collected alternative movie posters for 20 of the best horror movies (OK, the Harry Potter one is not technically horror, but the poster was too good to pass up).